Inspection method and inspection apparatus

ABSTRACT

There is established an easier inspection method with which it is not required to set up probes on wires. Also, there is provided an inspection apparatus using this inspection method. With the inspection apparatus or inspection method, primary coils of an inspection substrate and secondary coils of a device substrate are superimposed on each other so that a certain space is maintained therebetween. An AC signal is inputted into the primary coils, thereby generating an electromotive force in each secondary coil by electromagnetic induction. Then, each circuit provided on the device substrate is driven using the electromotive force and information possessed by an electromagnetic wave or electric field generated in this circuit is monitored, thereby detecting each defective spot.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an inspection apparatus used fora device substrate of a semiconductor device and to an inspection methodusing the inspection apparatus. More particularly, the present inventionrelates to an inspection apparatus of non-contact type and an inspectionmethod using the inspection apparatus.

[0003] 2. Description of the Related Art

[0004] In recent years, attentions have been given to a technique offorming a thin-film transistor (TFT) using a semiconductor film (whosethickness is about several nm to several hundred nm) formed on asubstrate having an insulating surface. This is because there isincreasing demand for an active matrix semiconductor display device thatis one type of semiconductor devices. Typical examples of the activematrix semiconductor display device include a liquid crystal display, anOLED (organic light emitting device) display, and a DMD (digitalmicromirror device).

[0005] It is possible to obtain a high mobility with a TFT (crystallineTFT) that uses a semiconductor film having a crystal structure as anactive layer. Therefore, it is possible to realize an active matrixsemiconductor display device that performs high-definition image displayby integrating functional circuits on the same substrate.

[0006] By the way, the active matrix semiconductor display device isobtained through various manufacturing steps. In the case of an activematrix liquid crystal display, for instance, there are mainly included apattern forming step for forming a semiconductor film and performingpattern formation, a color filter forming step for realizingcolorization, a cell assembling step for forming a liquid crystal panelby sealing a liquid crystal between a device substrate having an elementincluding a semiconductor and an opposing substrate having an opposingelectrode, and a module assembling step for finishing the liquid crystalpanel as a liquid crystal display by attaching driving parts for drivingthe liquid crystal panel and a backlight to the liquid crystal panelassembled in the cell assembling step.

[0007] The manufacturing steps described above also include aninspection step, although this inspection step differs to some extentdepending on which type of the liquid crystal display will be produced.If it is possible to find defective items at an early stage in themanufacturing steps before the liquid crystal display is finished as aproduct, it becomes possible to omit the following manufacturing stepsfor each of the defective panels. Accordingly, the inspection step is anextremely effective means from the viewpoint of cost reduction.

[0008] One type of the inspection step included in the pattern formingstep is a defect inspection that is performed after the patternformation.

[0009] The defect inspection after the pattern formation means aninspection for detecting each spot, in which a malfunction occurs due tovariations in the width of a semiconductor film pattern, insulating filmpattern, or wire pattern (hereinafter simply referred to as the“pattern”), after the pattern formation. Alternatively, the defectinspection means an inspection for detecting each spot in which wirebreaking or a short circuit occurs due to dust or a film formationfailure. Also, in some cases, the defect inspection means an inspectionfor confirming whether a circuit or a circuit element that is aninspection target operates normally.

[0010] Such defect inspections are broadly divided into an opticalinspection method and a probe inspection method.

[0011] The optical inspection method refers to an inspection method withwhich a pattern formed on a substrate is read using a CCD or the likeand each defect is identified by comparing the read pattern with areference pattern. Also, the probe inspection method means an inspectionmethod with which minute pins (probes) are set up on terminals on thesubstrate side and each defect is identified with reference to themagnitude of a current or a voltage flowing between the probes. Ingeneral, the former method is called the “non-contact type inspectionmethod”, while the latter method is called the “sensing pin typeinspection method”.

[0012] It is possible to detect each defect of a device substrateregardless of which method described above is used. However, each of theinspection methods described above has a shortcoming.

[0013] In the case of the optical inspection method, if an inspection isperformed after the formation of several pattern layers is finished, itbecomes difficult to identify patterns formed as lower layers andtherefore it is difficult to detect each defective spot. However, if aninspection is performed each time a pattern is formed, the inspectionstep itself becomes complicated and the time taken by the wholemanufacturing steps is elongated. Also, in the case of the probeinspection method, probes are directly set up on wires, so that theremay be cases where the wires are damaged and minute dust is caused. Thedust caused in the inspection step becomes a factor for the reduction ofyield in the following steps and therefore is not preferable.

SUMMARY OF THE INVENTION

[0014] In view of the problems described above, an object of the presentinvention is to establish an easier inspection method, with which it isnot required to set up probes on wires, and to provide an inspectionapparatus that uses the inspection method.

[0015] The inventors of the present invention have conceived that itbecomes possible to have a current flow through a wire of a devicesubstrate without setting up probes by generating an electromotive forcein the wire by means of electromagnetic induction.

[0016] In more detail, a substrate for inspection (inspection substrate)that will be used to inspect a device substrate is separately prepared.The inspection substrate includes primary coils, while the devicesubstrate that is an inspection target includes secondary coils.

[0017] It should be noted here that the primary coils and the secondarycoils are both formed by patterning a conductive film formed on asubstrate. Also, in the present invention, the primary coils and thesecondary coils are not coils having a structure where a magneticsubstance is provided at the center as a magnetic path but are coilshaving a structure where a magnetic substance is not provided at thecenter. Of course, coils having a structure where magnetic substance isprovided at the center can be used.

[0018] Then, the primary coils of the inspection substrate and thesecondary coils of the device substrate are superimposed on each otherso that a certain space is maintained therebetween. Following this, anelectromotive force is generated between two terminals of each secondarycoil by applying an AC voltage between two terminals of each primarycoil. Note that it is preferable that this space is reduced as much aspossible and a primary coil forming unit and a secondary coil formingunit are positioned so that a space between them is reduced as much aspossible to the extent that the space can be controlled.

[0019] Also, an AC voltage that is an electromotive force generated ineach secondary coil is rectified on the device substrate and thenappropriately flattened. In this manner, it becomes possible to use theAC voltage as a DC voltage (hereinafter referred to as the “power supplyvoltage”) for driving circuits or circuit elements of the devicesubstrate. Also, as to an AC voltage that is an electromotive forcegenerated in each secondary coil, the waveform of the AC voltage isappropriately rectified using a waveform shaping circuit or the like. Asa result, it becomes possible to use this AC voltage as a signal(hereinafter referred to as the “driving signal”) for driving circuitsor circuit elements of the device substrate.

[0020] Then, this driving signal or power supply voltage is inputtedinto wires of the device substrate.

[0021] The circuits or circuit elements formed on the substrate aredriven by the driving signal or power supply voltage inputted into theleading wires. When the circuits or circuit elements are driven, a weakelectromagnetic wave or electric field is generated in each circuit orcircuit element. By monitoring information possessed by this weakelectromagnetic wave or electric field, it becomes possible to detecteach spot, out of the plurality of circuits or circuit elements, thatdoes not operate normally.

[0022] It should be noted here that it is possible to collect theinformation possessed by the electromagnetic wave or electric field invarious dimensions, such as a frequency, phase, strength, and time. Inthe present invention, it is possible to use any kind of informationamong various information possessed by an electromagnetic wave orelectric field so long as it is possible to detect each spot, out of aplurality of circuits or circuit elements, that does not operatenormally.

[0023] It should be noted here that any publicly known method may beused to monitor a weak electromagnetic wave or electric field generatedin each circuit or circuit element.

[0024] With the present invention, there is realized the structuresdescribed above. Therefore, it becomes possible to detect each defectivespot without directly setting up probes on wires. As a result, there isprevented the reduction of yield in the following steps due to minutedust caused by the setting up of probes. In addition, unlike the opticalinspection method, it becomes possible to judge whether all of patternforming steps have been successfully done by a single inspection step.As a result, the inspection step is further simplified.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In the accompanying drawings:

[0026]FIGS. 1A and 1B are a top view of an inspection substrate and atop view of a device substrate, respectively;

[0027]FIG. 2 is a block diagram of the inspection substrate and thedevice substrate;

[0028]FIGS. 3A and 3B are each an enlarged view of a coil;

[0029]FIGS. 4A and 4B are each a perspective view of the inspectionsubstrate and the device substrate during an inspection;

[0030]FIG. 5 is a circuit diagram of a waveform shaping circuit;

[0031]FIG. 6 is a circuit diagram of a rectifier circuit;

[0032]FIGS. 7A and 7B each show how a pulsating signal obtained byrectifying an alternate current changes over time;

[0033]FIGS. 8A to 8C each show how a DC signal generated by combiningpulsating currents changes over time;

[0034]FIGS. 9A and 9B are respectively a perspective view of the devicesubstrate and a Pockels cell during an inspection and a drawing showinga pixel unit viewed through the Pockels cell during the inspection;

[0035]FIG. 10 is a block diagram of a device substrate of a liquidcrystal display;

[0036]FIG. 11 is a block diagram of a device substrate of an OLEDdisplay;

[0037]FIG. 12 is a top view of a device substrate;

[0038]FIG. 13 is a top view of a large device substrate;

[0039]FIG. 14 is a top view of another large device substrate;

[0040]FIG. 15 is a flowchart showing the flow of an inspection step ofthe present invention;

[0041]FIGS. 16A to 16D are each a top view or a cross-sectional view ofa coil; and

[0042]FIG. 17 is a block diagram of an inspection apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043]FIG. 1A is a top view of an inspection substrate for performing aninspection of the present invention. Also, FIG. 1B is a top view of adevice substrate to be inspected with an inspection method. Note that inthis embodiment, the inspection method of the present invention will bedescribed by taking, as an example, a device substrate of a liquidcrystal display. However, the usage of the inspection method of thepresent invention is not limited to the liquid crystal display but it ispossible to apply the inspection method to any other semiconductordevices so long as the semiconductor devices are formed usingsemiconductors.

[0044] As to the inspection substrate shown in FIG. 1A, primary coilforming units 101, external input buffer 102, and a connector connectingunit 103 are provided on a substrate 100. Note that in thisspecification, the inspection substrate includes the substrate 100 andall of circuits or circuit elements formed on the substrate 100.

[0045] As to the device substrate shown in FIG. 1B, a signal linedriving circuit 111, scanning line driving circuits 112, a pixel unit113, leading wires 114, connector connecting units 115, waveform shapingcircuits or rectifier circuits 116, secondary coil forming units 117,and coil wires 118 are provided on a substrate 110. Note that in thisspecification, the device substrate includes the substrate 110 and allof circuits or circuit elements formed on the substrate 110. Also, notethat the leading wires 114 are wires for supplying driving signals orpower supply voltages to the pixel unit and the driving circuitsprovided on the device substrate.

[0046] To each connector connecting unit 115, an FPC, a TAB, or the likeis connected in a step after an inspection step. Note that after theinspection step is finished, the device substrate is divided along thedotted line A-A′ so that the coil wires 118 are physically andelectrically separated.

[0047] Next, the operation performed for the device substrate and theinspection substrate in the inspection step will be described. Note thatto make it easy to understand the flows of signals in the inspectionstep, the structures of the device substrate and the inspectionsubstrate shown in FIGS. 1A and 1B are shown in the block diagram inFIG. 2. The structures of the device substrate and the inspectionsubstrate will be described with reference to FIGS. 1A, 1B, and 2.

[0048] On the inspection substrate 203, an AC signal for inspection isinputted from a signal source 201 or an AC power supply 202 into theexternal input buffer 102 via a connector connected to the connectorconnecting unit 103. The AC signal for inspection is buffer-amplified inthe external input buffer 102 and is inputted into the primary coilforming unit 101.

[0049] It should be noted here that in FIGS. 1A and 2, the inputted ACsignal is buffer-amplified in the external input buffer 102 and isinputted into the primary coil forming unit 101, although the presentinvention is not limited to this structure. The AC signal may bedirectly inputted into the primary coil forming unit 101 withoutproviding the external input buffer 102.

[0050] In the primary coil forming unit 101, there are formed aplurality of primary coils. The AC signal is inputted into each primarycoil.

[0051] On the other hand, in the secondary coil forming unit 117 of thedevice substrate 204, there are formed a plurality of secondary coilscorresponding to the plurality of primary coils of the primary coilforming unit 101. When an AC signal is inputted into each primary coil,an AC voltage that is an electromotive force is generated between twoterminals of each secondary coil by electromagnetic induction.

[0052] The AC voltage generated in each secondary coil is supplied to awaveform shaping circuit 116 a or a rectifier circuit 116 b. In thewaveform shaping circuit 116 a or the rectifier circuit 116 b, the ACvoltage is shaped or rectified, thereby generating a driving signal or apower supply voltage.

[0053] The generated driving signal or power supply voltage is inputtedinto the leading wires 114 via the coil wires 118. The inputted drivingsignal, power supply voltage, or the like is supplied to the signal linedriving circuit 111, the scanning line driving circuit 112, and thepixel unit 113 via the leading wires 114.

[0054] It should be noted here that a plurality of pixels are formed inthe pixel unit 113 and a pixel electrode is formed in each pixel. Notethat the number of the signal line driving circuits and the number ofthe scanning line driving circuits are not limited to those shown inFIGS. 1A and 2.

[0055] When a driving signal, power source voltage, or the like isinputted into the signal line driving circuit 111, the scanning linedriving circuit 112, or the pixel unit 113, an electromagnetic wave oran electric field is generated in each circuit or circuit element of thesignal line driving circuit 111, the scanning line driving circuit 112,or the pixel unit 113.

[0056] The strength of the electric field and the electromagnetic wavegenerated in each defective circuit or circuit element greatly differsfrom the strength of an electric field and an electromagnetic wavegenerated in each normal circuit or circuit element. As a result, itbecomes possible to track down each defective spot by monitoring thestrength of the electromagnetic wave and the electric field generated ineach circuit or circuit element. In FIG. 2, an inspection unit 205detects each defective spot by measuring the strength of the electricfield or the electromagnetic wave.

[0057] Also, the output from each circuit that is an inspection targetmay be inputted into a circuit dedicated to inspection (hereinafter,then “inspection dedicated circuit”) and the strength of an electricfiled or electromagnetic wave generated in the inspection dedicatedcircuit may be measured, thereby judging the presence or absence ofdefects or identifying each defective spot itself.

[0058] In the case where the inspection dedicated circuit is used, apixel dedicated to inspection (dummy pixel) that is not used for theactual display may be provided in the pixel unit and the output from acircuit or circuit element in the pixel dedicated to inspection may beinputted into the inspection dedicated circuit. This is not limited tothe pixel unit and it is not required to input the outputs from allcircuits or circuit elements of the device substrate into the inspectiondedicated circuit. That is, some of the circuits or circuit elements maybe selected and the outputs from the selected circuits or circuitelements may be inputted into the inspection dedicated circuit. Also, adummy circuit or circuit element dedicated to inspection that is notused for the actual driving may be formed and the output from thecircuit or circuit element dedicated to inspection may be inputted intothe inspection dedicated circuit.

[0059] It should be noted here that it does not matter which method isused to monitor an electromagnetic wave and an electric field so long asthe method has a sensitivity with which it is possible to detect thedefects of circuits or circuit elements.

[0060] Next, the detailed structures of the primary coil forming unitand the secondary coil forming unit (hereinafter collectively referredto as the “coil forming unit”) will be described. FIGS. 3A and 3B areeach an enlarged view of a coil.

[0061] The coil shown in FIG. 3A is spirally wounded while drawingcurves and coil terminals 301 and 302 are formed at both ends of thecoil. Also, the coil shown in FIG. 3B is spirally wounded while drawingrectangles and coil terminals 303 and 304 are formed at both ends of thecoil.

[0062] It should be noted here that it is enough that each coil used inthe present invention has a shape where the wire of the coil is whollyformed in the same plane and is spirally wounded. Consequently, ifviewed in a direction perpendicular to the plane on which the coil isformed, it does not matter whether the wire of the coil draws curves ora shape having comers.

[0063] Also, it is possible for a designer to appropriately set thenumber of turns of the coil, the line width thereof, and an area on thesubstrate occupied by the coil.

[0064] Next, a state where the device substrate having the coil shown inFIG. 3A as a primary coil and the inspection substrate, which similarlyhas the coil shown in FIG. 3A as a secondary coil, are superimposed oneach other is shown in FIG. 4A. Note that reference numeral 205 denotesan FPC that connects the inspection substrate 203 to the signal sourceand the AC power supply.

[0065] As shown in FIG. 4A, each primary coil forming unit 101 of theinspection substrate 203 and each secondary coil forming unit 117 of thedevice substrate 204 are superimposed on each other so that a certainspace is maintained therebetween. Note that it is preferable that thisspace is reduced as much as possible and the primary coil forming unit101 and the secondary coil forming unit 117 of the device substrate 204are positioned as close to each other as possible to the extent thatthis space can be controlled.

[0066] It should be noted here that the space between the inspectionsubstrate 203 and the device substrate 204 may be maintained by fixingthese substrates or be maintained by fixing the device substrate 204 andhaving a liquid or a gas flow between the inspection substrate 203 andthe device substrate 204 at a constant flow rate or under a constantpressure.

[0067] An enlarged view of a portion, in which the primary coil formingunit 101 and the secondary coil forming unit 117 are superimposed oneach other, is shown in FIG. 4B. Reference numeral 206 denotes theprimary coils and reference numeral 207 represents the secondary coils.

[0068] The primary coils 206 and the secondary coils 207 are formed sothat the wires thereof are spirally wounded in the same direction,although the present invention is not limited to this structure. Thatis, there occurs no problem even if the winding direction of the primarycoils is opposite to the winding direction of the secondary coils.

[0069] Also, it is possible for a designer to appropriately set thespace between the primary coils and the secondary coils (L_(gap)).

[0070] Next, the detailed structure of the waveform shaping circuit 116a shown in FIG. 2 will be described.

[0071]FIG. 5 shows a state where the signal source 201, the primary coilforming unit 101, the secondary coil forming unit 117, and the waveformshaping circuit 116 a shown in FIGS. 1A, 1B, and 2 are connected to eachother. A plurality of primary coils 206 are provided in the primary coilforming unit 101, while a plurality of secondary coils 207 are providedin the secondary coil forming unit 117.

[0072] An AC signal for inspection is inputted from the signal source201 into each primary coil 206. When the AC signal is inputted into theprimary coil 206, an AC voltage that is an electromotive force isgenerated in a corresponding secondary coil 207 and this AC voltage isapplied to the waveform shaping circuit 116 a.

[0073] The waveform shaping circuit 116 a is an electronic circuit thatis used to shape or rectify the changing amount over time, which is tosay the waveform of a voltage, a current, or the like. In FIG. 5, thewaveform shaping circuit 116 a includes resistors 501 and 502 andcapacitors 503 and forms an integration type waveform shaping circuit116 a by assembling each circuit element. Needless to say, the waveformshaping circuit is not limited to the structure shown in FIG. 5. Also,like a power circuit, a waveform shaping operation may be performedusing a detector circuit that uses a diode. The waveform shaping circuit116 a used in the present invention generates and outputs, specifically,a clock signal (CLK), a start pulse signal (SP), and a video signal(Video signals) from an inputted AC electromotive force. Note that thesignals outputted from the waveform shaping circuit 116 a are notlimited to those described above. That is, any other signals havingdifferent waveforms may be outputted so long as it is possible togenerate, in the circuit or circuit element of the device substrate, anelectromagnetic wave or an electric field with which it is possible toidentify each defective spot through monitoring.

[0074] The signals outputted from the waveform shaping circuit 116 a areinputted into circuits in subsequent stages (in FIGS. 1A, 1B, and 2, thesignal line driving circuit 111, the scanning line driving circuit 112,and the pixel unit 113).

[0075] Next, the detailed structure of the rectifier circuit 116 b shownin FIG. 2 will be described.

[0076]FIG. 6 shows a state where the AC power supply 202, the primarycoil forming unit 101, the secondary coil forming unit 117, and therectifier circuit 116 b shown in FIGS. 1A, 1B, and 2 are connected toeach other. A plurality of primary coils 206 are provided in the primarycoil forming unit 101, while a plurality of secondary coils 207 areprovided in the secondary coil forming unit 117.

[0077] An AC signal for inspection is inputted from the AC power supply202 into each primary coil 206. When the AC signal is inputted into theprimary coil 206, an AC voltage that is an electromotive force isgenerated in a corresponding secondary coil 207 and this AC voltage isapplied to the rectifier circuit 116 b.

[0078] It should be noted here that in the present invention, therectifier circuit means a circuit that generates a DC power supplyvoltage from the supplied AC voltage. Note that the DC power supplyvoltage means a voltage whose height is maintained constant.

[0079] The rectifier circuit 116 b shown in FIG. 6 includes diodes 601,capacitors 602, and resistors 603. Each diode 601 rectifies the inputtedAC voltage and converts it into a DC voltage.

[0080]FIG. 7A shows how an AC voltage that is not yet rectified by thediode 601 changes over time. Also, FIG. 7B shows how a voltage that hasbeen rectified changes over time. As can be seen by comparing the graphin FIG. 7A with the graph in FIG. 7B, after the rectification, thevoltage becomes a so-called pulsating voltage that takes “0” or a valuehaving a polarity on one side each half period.

[0081] It is impossible to use the pulsating voltage shown in FIG. 7B asa power supply voltage. Therefore, in usual cases, the pulsating currentis flattened and is converted into a DC voltage by accumulating chargesin the capacitor. However, if a large-capacity capacitor is formed tomake it possible to sufficiently flatten the pulsating current using athin-film semiconductor, the area of the capacitor itself becomesextremely large. Therefore, this method is unrealistic. In view of thisproblem, in the present invention, pulsating voltages having differentphases are rectified and then synthesized (combined), thereby flatteningthe voltages. With the structure described above, it becomes possible tosufficiently flatten a pulsating current even if the capacity of thecapacitor is small. Further, it becomes possible to sufficiently flattenthe pulsating current even if a capacitor is not specially provided.

[0082] In FIG. 6, by inputting AC signals, whose phases are differentfrom each other, into four primary coils, four pulsating voltages havingdifferent phases are outputted from four diodes 601. Then, the fourpulsating voltages described above are combined and a DC power supplyvoltage, whose height is maintained approximately constant, is generatedand outputted to circuits in subsequent stages.

[0083] It should be noted here that in FIG. 6, a power supply voltage isgenerated by combining four pulsating signals having different phasesthat are outputted from the four diodes 601. However, the presentinvention is not limited to this structure. That is, the number of phasesplits is not limited to this and any other number of phase splits maybe used so long as it is possible to flatten the output from therectifier circuit and use this output as a power supply voltage.

[0084]FIGS. 8A and 8B each show how a power supply voltage obtained bycombining a plurality of rectified signals changes over time. FIG. 8Ashows an example in which one power supply voltage is generated bycombining four pulsating voltages having different phases.

[0085] It should be noted here that the power supply voltage isgenerated by combining a plurality of pulsating currents, so that thereexists a ripple that is a component other than a direct current. Thisripple is the equivalent of a difference between the highest voltage andthe lowest voltage of a power supply voltage. The power supply voltagebecomes more similar to a direct current in accordance with thereduction of the ripple.

[0086]FIG. 8B shows how a power supply voltage obtained by combiningeight pulsating voltages having different phases changes over time. Itcan be seen that the ripple becomes small in comparison with thechanging of the power supply voltage over time shown in FIG. 8A.

[0087]FIG. 8C shows how a power supply voltage obtained by combining 16pulsating voltages having different phases changes over time. It can beseen that the ripple becomes small in comparison with the changing ofthe power supply voltage over time shown in FIG. 8B.

[0088] As described above, it can be understood that the ripple of apower supply voltage becomes smaller and the voltage becomes moresimilar to a direct current by combining more pulsating currents whosephases are different from each other. As a result, it becomes easier toflatten a power supply voltage outputted from the rectifier circuit inaccordance with the increase of the number of phase splits. Also, itbecomes easier to flatten the power supply voltage outputted from therectifier circuit in accordance with the increase of the capacity of thecapacitor 602.

[0089] The power supply voltage generated in the rectifier circuit 116 bis outputted from the terminals 610 and 611. In more detail, a voltageclose to the ground is outputted from the terminal 610 and a powersupply voltage having the positive polarity is outputted from theterminal 611. Note that it is possible to reverse the polarity of theoutputted power supply voltage by inversely connecting the anode andcathode of the diode. The diode 602 is connected to the terminals 610and 611 so that the anode and cathode thereof are connected in aninverse manner with respect to the diode 601 connected to the terminals612 and 613. Accordingly, a voltage close to “0” is outputted from theterminal 612 and a power supply voltage having a negative polarity isoutputted from the terminal 613.

[0090] It should be noted here that various circuits or circuit elementsare formed on the device substrate and the height of a power supplyvoltage that should be supplied to each circuit or circuit elementdiffers depending on the type or use of the circuit or circuit element.In the rectifier circuit shown in FIG. 6, it is possible to adjust theheight of a voltage to be inputted into each terminal by adjusting theamplitude of an inputted AC signal. Further, it is possible to changethe heights of power supply voltages to be supplied to circuits orcircuit elements by changing the terminals to which the circuits orcircuit elements are connected.

[0091] The rectifier circuit used in the present invention is notlimited to the structure shown in FIG. 6. It does not matter whichcircuit is used as the rectifier circuit in the present invention solong as the circuit is capable of generating a DC power supply voltagefrom an inputted AC signal.

[0092] In this embodiment mode, there has been described an example inwhich the device substrate includes the signal line driving circuit andthe scanning line driving circuit that are driving circuits. However,the device substrate to be inspected with the present invention is notlimited to this. Even in the case where the device substrate has onlythe pixel unit, it is possible to perform an inspection using theinspection method of the present invention. Also, even in the case of asingle element called “TEG” or an evaluation circuit in which singleelements are combined, it is possible to inspect defects using theinspection method and the inspection apparatus of the present invention.

[0093] Also, in this embodiment mode, there has been described aninspection method for a device substrate of a liquid crystal display,although it is possible to inspect even a semiconductor display deviceother than the liquid crystal display using the inspection methoddescribed in this embodiment mode. Also, the application of the presentinvention is not limited to a semiconductor display device but it ispossible to inspect a semiconductor device using the inspection methodof the present invention so long as the semiconductor device uses thecharacteristics of a semiconductor formed on a substrate. Note that thesemiconductor device may be a semiconductor device that uses asemiconductor thin film formed on a glass substrate or be asemiconductor device formed on a single crystalline silicon substrate.

[0094] However, it is required to appropriately set the number anddesign of the primary coils and the number and design of the secondarycoils in accordance with the type and specifications of thesemiconductor device. It is also required to appropriately set thewaveform, frequency, and amplitude of the AC signal for inspection to beinputted into the primary coil forming unit in accordance with the typeand specifications of the semiconductor device.

[0095] With the present invention, there is obtained the structuredescribed above. As a result, it becomes possible to detect eachdefective spot without directly setting up probes on wires. This makesit possible to prevent the reduction in yield in the following steps dueto minute dust caused by the setting up of the probes. In addition,unlike the optical inspection method, it becomes possible to judgewhether all of pattern forming steps have been successfully done or notby a single inspection step. Therefore, the inspection step is moresimplified.

EMBODIMENTS

[0096] Embodiments of the present invention will be described below.

First Embodiment

[0097] In this embodiment, there will be described an example in whichan electric field generated in each circuit or circuit element isdetected using an electrooptic effect in an inspection step. In moredetail, in this embodiment, there will be described an example in whichmeasurements are performed using a Pockels cell.

[0098] The Pockels cell is one type of an electrooptic element that usesthe Pockels effect that is one electrooptic effect. Note that theelectrooptic element is an element that uses an electrooptic effect withwhich a refractive index is changed by the application of an electricfield. By utilizing this property, it becomes possible to use theelectrooptic element as a shutter, and to use it to modulate light, andto generate or detect circular polarization by applying an AC voltage ora pulse voltage to a crystal.

[0099]FIG. 9A shows a state where a device substrate 901 of a liquidcrystal display and a Pockels cell 909 are superimposed on each other.

[0100] The device substrate 901 includes secondary coil forming units902, scanning line driving circuits 903, a pixel unit 904, and a signalline driving circuit 905. Also, a driving signal and power supplyvoltage for inspection are inputted into each of the scanning linedriving circuits 903, the pixel unit 904, and the signal line drivingcircuit 905 by an AC voltage generated in the secondary coil formingunits 902.

[0101] The Pockels cell 909 includes a first electrode 906, a secondelectrode 907, and a Pockels crystal 908 that is a ferroelectricsubstance crystal. The Pockels crystal 908 is sandwiched between thefirst electrode 906 and the second electrode 907, with the firstelectrode 906 and the second electrode 907 being arranged perpendicularto the direction of the optical axis of the Pockels crystal 908.

[0102] The first electrode 906 and the second electrode 907 are formedusing a conductive material through which light is capable of passing.Indium-tin oxide (ITO) is used in FIG. 9A, although the material of thefirst electrode and the second electrode of the present invention is notlimited to this.

[0103] A constant voltage is applied to the first electrode 906. Notethat in FIG. 9A, the first electrode 906 is connected to the ground.Also, the first electrode 906 and the second electrode 907 are arrangedparallel to the device substrate 901. In addition, the device substrate901 is arranged on the second electrode 907 side. Note that the secondelectrode 907 may be arranged so as to contact the device substrate 901or be arranged so that a certain space is maintained therebetween. Also,a component functioning as a cushion may be sandwiched between thesecond electrode 907 and the device substrate 901.

[0104] Also, in FIG. 9A, the Pockels cell 909 is arranged so as to besuperimposed on the pixel unit 904. FIG. 9B shows a state of the Pockelscell 909 viewed from the arrow direction in FIG. 9A.

[0105] A plurality of signal lines 910 and a plurality of scanning lines911 are formed in the pixel unit 904 and the areas surrounded by thesignal lines 910 and the scanning lines 911 are the equivalent of pixels912. In each pixel 912 (912 a and 912 b), there is provided a pixelelectrode 913 (913 a or 913 b).

[0106] Assuming that among the pixels 912, the pixel 912 a is anon-defective and normal pixel and the pixel 912 b is a defective pixel,a portion of the Pockels cell 909 superimposed on the pixel electrode913 a differs from a portion superimposed on the pixel electrode 913 bin the light transmittance in the arrow direction.

[0107] This is because if the device substrate is arranged perpendicularto the optical axis of the ferroelectric substance crystal of thePockels cell, birefringence is caused in the ferroelectric substancecrystal due to the electric field generated in the circuit or circuitelement.

[0108] The refractive index of this birefringence exhibited fordeflection having an electric field direction component is determined bythe strength of an electric field. Consequently, in a plurality ofcircuits or circuit elements that have the same structure and operatenormally, there occur electric fields having the same strength. As aresult, in portions, in which the ferroelectric substance crystal issuperimposed on each circuit or circuit element, the refractive index ofthe ferroelectric substance crystal becomes approximately the same.

[0109] However, an electric field generated in a defective circuit orcircuit element may be stronger or weaker than an electric fieldgenerated in another normal circuit or circuit element. Accordingly, therefractive index of each portion of the ferroelectric substance crystalthat is superimposed on a defective circuit or circuit element differsfrom the refractive index of each portion of the ferroelectric substancecrystal that is superimposed on another normal circuit or circuitelement. As a result, when the device substrate is viewed through thePockels cell, each portion that is superimposed on a defective circuitor circuit element looks brighter or darker than each portion that issuperimposed on a normal circuit or circuit element.

[0110] As a result, it becomes possible to calculate transmittance ofthe Pockels cell and detect each defective spot by separating light ineach pixel traveling in a direction perpendicular to the devicesubstrate using an optical system such as a polarizing beam splitter andby monitoring the strength of the separated light. In FIG. 9B, it can beseen that a defect occurs in the pixel 912 b. Note that the detection ofeach defective spot may be performed by carrying out calculationprocessing of some kind for results obtained by a plurality ofmonitoring operations.

[0111] Also, the presence or absence of defects may be judged ordefective spots themselves may be identified by inputting the outputsfrom all circuits that are inspection targets into the inspectiondedicated circuit and measuring the strength of an electric fieldgenerated in the inspection dedicated circuit using an electroopticdevice. By using the inspection dedicated circuit, it becomesunnecessary to monitor each circuit or circuit element that is aninspection target using the Pockels cell. As a result, it becomespossible to simplify the inspection step and to perform the inspectionstep swiftly.

[0112] It should be noted here that in this embodiment, there has beendescribed an example in which each defect of the pixel unit 904 isdetected, although this embodiment is not limited to this. It ispossible to detect each defective spot in a like manner by superimposingthe Pockels cell 909 on the scanning line driving circuits 903 and thesignal line driving circuit 905 and by monitoring a refractive index. Itis also possible to similarly detect defects, such as wire breaking andshort circuits, occurring in the leading wires on the device substrate.

[0113] It should be noted here that a crystal, such as NH₄H₂PO₄, BaTiO₃,KH₂PO₄ (KHP), KD₂PO₄ (KDP), LiNbO₃, ZnO, is be mainly used as thePockels crystal. However, the Pockels crystal that can be used in thisembodiment is not limited to the crystals described above. That is, anyother crystal may be used so long as the crystal has the Pockels effect.

[0114] Also, the Pockels cell is used in this embodiment, although theelectrooptic device for sensing the strength of an electric field is notlimited to this. That is, it is possible to use any other electroopticdevice for the inspection method or inspection apparatus of the presentinvention so long as the electrooptic device uses a phenomenon where itsoptical properties is changed by the application of a voltage.Consequently, it is possible to use a liquid crystal or the like.

Second Embodiment

[0115] In this embodiment, the driving signal and power supply voltagefor inspection will be described in more detail by taking, as examples,cases of a liquid crystal display and an OLED display.

[0116] The number of the primary coils and the number of the secondarycoils are changed in accordance with the structures of the pixel unitand the driving circuit of the device substrate, so that it is importantto set these numbers in accordance with the specifications of eachdevice substrate.

[0117]FIG. 10 shows the structure of a device substrate of a generalliquid crystal display. The device substrate shown in FIG. 10 includes asignal line driving circuit 700, a scanning line driving circuit 701,and a pixel unit 702.

[0118] A plurality of signal lines and a plurality of scanning lines areformed in the pixel unit 702 and the areas surrounded by the signallines and the scanning lines are the equivalent of pixels. Note that inFIG. 10, among a plurality of pixels, only a pixel having one signalline 703 and one scanning line 704 is shown as a representative example.Each pixel includes a pixel TFT functioning as a switching element and apixel electrode 706 of a liquid crystal cell.

[0119] A gate electrode of the pixel TFT 705 is connected to thescanning line 704. Also, the source region and the drain region of thepixel TFT 705 are connected to the signal line 703 and the pixelelectrode 706, respectively.

[0120] The signal line driving circuit 700 includes a shift register710, a level shifter 711, and an analog switch 712. A power supplyvoltage (Power supply) is given to the shift register 710, the levelshifter 711, and the analog switch 712. Also, a clock signal (S-CLK) anda start pulse signal (S-SP) for a signal line driving circuit are givento the shift register 710. Further, a video signal (Video signals) isgiven to the analog switch 712.

[0121] When a clock signal (S-CLK) and a start pulse signal (S-SP) areinputted into the shift register 710, a sampling signal that determinesthe timings for sampling the video signal is generated and inputted intothe level shifter 711. As to the sampling signal, the amplitude of itsvoltage is increased in the level shifter 711. Then, the sampling signalis inputted into the analog switch 712. In the analog switch 712, theinputted video signal is sampled in synchronization with the inputtedsampling signal and is inputted into the signal line 703.

[0122] On the other hand, the scanning line driving circuit includes ashift register 721 and a buffer 722. A power supply voltage (Powersupply) is given to the shift register 721 and the buffer 722. Also, aclock signal (G-CLK) and a start pulse signal (G-SP) for the scanningline driving circuit are given to the shift register 721.

[0123] When the clock signal (G-CLK) and the start pulse signal (G-SP)are inputted into the shift register 721, a selection signal thatdetermines the timings for selecting the scanning lines is generated andinputted into the buffer 722. The selection signal inputted into thebuffer 722 is buffer-amplified and is inputted into the scanning line704.

[0124] When the scanning line 704 is selected, the pixel TFT 705, whosegate electrode is connected to the selected scanning line 704, is turnedon. Then, the video signal that has been sampled and inputted into thesignal line is inputted into the pixel electrode 706 via the turned-onpixel TFT 705.

[0125] When the signal line driving circuit 700, the scanning linedriving circuit 701, and the pixel unit 702 operate in this manner, anelectric field or an electromagnetic wave is generated in each circuitor circuit element. By monitoring this electric field or electromagneticwave using a means of some kind, it becomes possible to detect eachdefective spot.

[0126] In the case of the device substrate shown in FIG. 10, the S-CLK,S-SP, G-CLK, G-SP, and video signal are inputted into each circuit asdriving signals for inspection. Note that the driving signals forinspection are not limited to the signals described above. It ispossible to use any other signals as the driving signals for inspectionso long as the signals relate to driving. For instance, aside from thesignals described above, there may be inputted a signal that determinesthe timings for switching scanning directions of the scanning lines, asignal that switches the direction in which the selection signal isinputted into the scanning lines, or the like. However, it is importantto input a signal, with which it is possible to detect the presence orabsence of defects in circuits or circuit elements, into a circuit forwhich an inspection should be performed.

[0127] Also, in the case where not all of circuits of a device substratebut some out of the circuits should be subjected to an inspection, if itis possible to detect defective portions of the circuits, it is notrequired to input all of the driving signals described above. Forinstance, if only the shift register 710 of the signal line drivingcircuit 700 should be subjected to an inspection, it is enough that onlythe S-CLK and S-SP that are driving signals for inspection and a powersupply voltage for inspecting the shift register 710 are generated inthe waveform shaping circuit and the rectifier circuit and are inputtedinto the shift register 710.

[0128] Next, the structure of the device substrate of a general OLEDdisplay is shown in FIG. 11. Note that FIG. 11 illustrates, as anexample, a driving circuit of an OLED display that displays an imageusing digital video signals. The device substrate shown in FIG. 11includes a signal line driving circuit 800, a scanning line drivingcircuit 801, and a pixel unit 802.

[0129] A plurality of signal lines, a plurality of scanning lines, and aplurality of power supply lines are formed in the pixel unit 802 and theareas surrounded by the signal lines, the scanning lines, and the powersupply lines are the equivalent of pixels. Note that in FIG. 11, among aplurality of pixels, only a pixel having one signal line 807, onescanning line 809, and one power supply line 808 is shown as arepresentative example. Each pixel includes a switching TFT 803functioning as a switching element, a driving TFT 804, a holdingcapacitor 805, and a pixel electrode 806 of the OLED.

[0130] The gate electrode of the switching TFT 803 is connected to thescanning line 809 and has the source region and the drain region, one ofwhich is connected to the signal line 807 and the other one of which isconnected to the gate electrode of the driving TFT 804.

[0131] The driving TFT 804 has the source region and the drain region,one of which is connected to the power supply line 808 and the other oneof which is connected to the pixel electrode 806. Also, the holdingcapacitor 805 is formed by the gate electrode of the driving TFT 804 andthe power supply line 808. Note that it is not necessarily required toform the holding capacitor 805.

[0132] The signal line driving circuit 800 includes a shift register810, a first latch 811, and a second latch 812. A power supply voltage(Power supply) is given to each of the shift register 810, the firstlatch 811, and the second latch 812. Also, a clock signal (S-CLK) and astart pulse signal (S-SP) for the signal line driving circuit are givento the shift register 810. Further, a latch signal (Latch signals) thatdetermines the timings for latching and a video signal (Video signals)are given to the first latch 811.

[0133] When the clock signal (S-CLK) and the start pulse signal (S-SP)are inputted into the shift register 810, a sampling signal thatdetermines the timings for sampling the video signal is generated andinputted into the first latch 811.

[0134] It should be noted here that the sampling signal from the shiftregister 810 may be inputted into the first latch 811 after beingbuffer-amplified by a buffer or the like. A wire into which the samplingsignal is inputted has a large load capacity (parasitic capacitance)because many circuits or circuit elements are connected to this wire.This buffer is effective at preventing a situation where the leadingedge and trailing edge of the timing signal is “slowly moving” due tothis large load capacity.

[0135] The first latch 811 includes latches in a plurality of stages. Inthis first latch 811, an inputted video signal is sampled and is storedin the latch in each stage in succession in synchronization with aninputted sampling signal.

[0136] A period of time taken to complete the writing of the videosignal into the latch in each stage of the first latch 811 is called a“line period”. In actual cases, the line period may include a horizontalblanking period.

[0137] When one line period is finished, a latch signal is inputted intothe second latch 812. At this instant, the video signal written into thefirst latch 811 and is held therein is simultaneously sent to the secondlatch 812, in which the video signal is written into the latch in eachstage of the second latch 812 and is held therein.

[0138] When the video signal has been sent from the first latch 811 tothe second latch 812, the writing of a video signal into the first latch811 is performed in succession on the basis of the sampling signal fromthe shift register 810.

[0139] In this second one line period, the video signal written into thesecond latch 812 and is held therein is inputted into a source signalline.

[0140] On the other hand, the scanning line driving circuit includes ashift register 821 and a buffer 822. A power supply voltage (Powersupply) is given to the shift register 821 and the buffer 822. Also, aclock signal (G-CLK) and a start pulse signal (G-SP) for the scanningline driving circuit are given to the shift register 821.

[0141] When the clock signal (G-CLK) and the start pulse signal (G-SP)are inputted into the shift register 821, a selection signal thatdetermines the timings for selecting the scanning lines is generated andinputted into the buffer 822. The selection signal inputted into thebuffer 822 is buffer-amplified and inputted into the scanning line 809.

[0142] When the scanning line 809 is selected, the switching TFT 803,whose gate electrode is connected to the selected scanning line 809, isturned on. Then, the video signal inputted into the signal line isinputted into the gate electrode of the driving TFT 804 via theturned-on switching TFT 803.

[0143] The switching of the driving TFT 804 is controlled on the basisof the information “1” or “0” contained in the video signal inputtedinto the gate electrode. When the driving TFT 804 is turned on, thepotential of the power supply line is given to the pixel electrode. Whenthe driving TFT 804 is turned off, the potential of the power supplyline is not given to the pixel electrode.

[0144] When the signal line driving circuit 800, the scanning linedriving circuit 801, and the pixel unit 802 operate in this manner, anelectric field or an electromagnetic wave is generated in each circuitor circuit element. By monitoring this electric field or electromagneticwave using a means of some kind, it becomes possible to detect eachdefective spot.

[0145] In the case of the device substrate shown in FIG. 11, the S-CLK,S-SP, G-CLK, G-SP, a latch signal, and a video signal are inputted intoeach circuit as driving signals for inspection. Note that the drivingsignals for inspection are not limited to the signals described above.It is possible to use any other signals as the driving signals forinspection so long as the signals relate to driving. For instance, asidefrom the signals described above, there may be inputted a signal thatdetermines the timings for switching the scanning directions of thescanning lines, a signal that switches the direction in which aselection signal is inputted into the scanning lines, or the like.However, it is important to input a signal with which it is possible todetect the presence or absence of defects in circuits or circuitelements in a circuit for which an inspection should be performed.

[0146] Also, in the case where not all of circuits of a device substratebut some of the circuits are regarded as inspection targets, if it ispossible to detect defective portions of the circuits, it is notrequired to input all of the driving signals described above. Forinstance, if only the shift register 810 of the signal line drivingcircuit 800 should be subjected to an inspection, it is enough that onlythe S-CLK and S-SP that are driving signals for inspection and a powersupply voltage for inspecting the shift register 810 are generated inthe waveform shaping circuit and the rectifier circuit and are inputtedinto the shift register 810.

[0147] It should be noted here that in the case where a power supplyvoltage is generated by combining a plurality of pulsating signalshaving different phases, the number of the primary coils is alsoaffected by the number of the combined pulsating signals.

[0148] It should be noted here that the scope of application of theinspection apparatus and the inspection method of the present inventionis not limited to the device substrates having the structures shown inFIGS. 10 and 11. It is possible to apply the inspection apparatus andthe inspection method of the present invention to any semiconductordevices regardless of their types and specifications so long as anelectromagnetic wave or an electric field is generated in each circuitor circuit element in the semiconductor devices by inputting a drivingsignal and a power supply voltage in a non-contact manner.

[0149] It is possible to carry out this embodiment by freely combiningthis embodiment with the first embodiment.

Third Embodiment

[0150] In this embodiment, there will be described a line for cutting asubstrate after an inspection is finished.

[0151]FIG. 12 is a top view of a device substrate to be inspected withthe inspection method of the present invention. Note that in thisembodiment, the inspection method of the present invention will bedescribed by taking, as an example, a device substrate of a liquidcrystal display. However, the use of the inspection method of thepresent invention is not limited to a liquid crystal display but may beused for any other semiconductor devices so long as the semiconductordevices are formed using semiconductors.

[0152] As to the device substrate shown in FIG. 12, a signal linedriving circuit 411, scanning line driving circuits 412, a pixel unit413, leading wires 414, connector connecting units 415, waveform shapingcircuits or rectifier circuits 416, secondary coil forming units 417,and coil wires 418 are provided on a substrate 410. Note that in thisspecification, the device substrate includes the substrate 410 and allcircuits or circuit elements formed on the substrate 410.

[0153] An FPC, a TAB, or the like is connected to each connectorconnecting unit 415 in a step following the inspection step.

[0154] After the inspection step is finished, the device substrate iscut along the dotted line B-B′ so that the leading wires 414 and thecoil wires 418 are physically and electrically separated from eachother. Note that in this embodiment, after a portion of the devicesubstrate is cut off, each secondary coil forming unit 417 is left onthe substrate that will be used to structure a semiconductor device. Thesecondary coil forming unit 417 and the leading wires 414 areelectrically and physically separated from each other, so that even ifthe secondary coil forming unit 417 is left on the substrate, thissecondary coil forming unit 417 does not interfere with the operation ofthe finished semiconductor device.

[0155] It should be noted here that it is not necessarily required toseparate the coil wires 418 at the same time as the cutting of thesubstrate. For instance, the coil wires 418 may be electricallyseparated using a laser or the like. As to the cutting of the coil wires418, it is enough that the secondary coil forming units 417 and thecircuits or circuit elements of the device substrate are electricallyseparated from each other.

[0156] It should be noted here that the waveform shaping circuits orrectifier circuits 416 may also be left on the substrate that will beused to structure the semiconductor device after the cutting or beformed on a substrate that will be not used to structure thesemiconductor device.

[0157] It is possible to carry out this embodiment by freely combiningthe structure of this embodiment with the structure in the first orsecond embodiment.

Fourth Embodiment

[0158] In this embodiment, there will be described the cutting of asubstrate after an inspection is finished in the case where a pluralityof substrates for display are formed using a large device substrate.

[0159]FIG. 13 is a top view of the large device substrate of thisembodiment that is not yet cut. In FIG. 13, by cutting the devicesubstrate along the dotted lines, nine substrates for display are formedfrom a single device substrate. Note that in this embodiment, there isshown an example in which nine substrates for display are formed from asingle substrate, although this embodiment is not limited to thisnumber.

[0160] It should be noted here that during the cutting, leading wiresand coil wires are cut and destroyed so that these wires are physicallyand electrically separated from each other. Also, in FIG. 13, after thecutting of the device substrate, there is obtained a situation whereeach secondary coil forming unit 1001 is provided on a substrate thatwill not be used for display.

[0161] As to a manner in which the large substrate is cut, an examplethat is different from the example shown in FIG. 13 will be described.FIG. 14 is a top view of another large device substrate of thisembodiment that is not yet cut. In FIG. 14, by cutting the devicesubstrate along the dotted lines, nine substrates for display are formedfrom a single device substrate. Note that in this embodiment, there isshown an example in which nine substrates for display are formed from asingle device substrate, although this embodiment is not limited to thisnumber.

[0162] It should be noted here that during the cutting, leading wiresand coil wires are cut and destroyed so that these wires are physicallyand electrically separated from each other. Also, in FIG. 14, eachsecondary coil forming unit 1002 is provided on a line for cutting thesubstrate and is cut and destroyed after the inspection is finished.After the inspection is finished, the secondary coil forming unit 1002becomes unnecessary, so that the secondary coil forming unit 1002 doesnot interfere with the operation of a finished semiconductor device.

[0163] It should be noted here that the waveform shaping circuit orrectifier circuit may be left on the substrate that will be used tostructure a semiconductor device after the cutting or be formed on asubstrate that will not be used to structure a semiconductor device.Also, the waveform shaping circuit or rectifier circuit may be destroyedafter the cutting.

[0164] It is possible to carry out this embodiment by freely combiningthe structure of this embodiment with the structures of the first tothird embodiments.

Fifth Embodiment

[0165] In this embodiment, the flow of the inspection step of thepresent invention will be described with reference to a flowchart.

[0166]FIG. 15 is a flowchart of the inspection step of the presentinvention. First, after a production step prior to an inspection isfinished, a power supply voltage or driving signal for inspection isinputted into circuits or circuit elements of the device substrate.

[0167] Then, under a state where the power supply voltage or drivingsignal for inspection is being inputted into the device substrate, thestrength of an electromagnetic wave or electric field generated in eachcircuit or circuit element of the device substrate that is an inspectiontarget is monitored using a publicly known measuring method.

[0168] Then, the strength of the generated electromagnetic wave orelectric field is compared with that generated in a circuit element thatoperates normally. Note that during this process, a measured value of acircuit or circuit element may be compared with a measured value ofanother circuit or circuit element. Alternatively, a value obtained froma theoretical value calculated by performing a simulation may becompared with a measured value.

[0169] Then, it is judged that each circuit or circuit element, in whichthere is generated an electromagnetic wave or electric field whosestrength has been judged as greatly differing from a reference value asa result of this comparison, as a defective spot. Accordingly, itbecomes possible to simultaneously determine the presence or absence ofdefective spots and identify the locations thereof. Note that it ispossible for a person who carries out the present invention toappropriately set the criteria for judging the strength of anelectromagnetic wave or electric field generated in each defective spotduring this process.

[0170] If there exist no defects, it is judged that the inspection isfinished at this point in time and a manufacturing step following theinspection step is started.

[0171] If there exists any defect, there is selected one out of (1) astep for terminating the attempt to finish the substrate as a product bydropping the substrate from the manufacturing steps (lot-out) or (2) astep for identifying the cause of the defect. Note that in the casewhere a plurality of products are to be produced from a single largesubstrate, the lot-out is performed after the cutting of the substrate.

[0172] In the case where the cause of the defect is identified and it isjudged that the repair of the defect is possible, it is possible thatthe inspection step of the present invention is performed again afterthe repair and the processes described are repeated. Conversely, if itis judged that the repair is impossible, the lot-out is performed atthis point in time.

[0173] It is possible to carry out this embodiment by freely combiningthe structure of this embodiment with the structures of the first tofourth embodiments.

Sixth Embodiment

[0174] In this embodiment, how a coil used in the present invention isconnected to terminals and wire (coil wire) of the coil will bedescribed in detail.

[0175] In FIG. 16A, a coil 1601 is formed on an insulating surface andan interlayer insulating film 1603 is formed on this insulating surfaceso as to cover the coil 1601. Also, a contact hole is formed in theinterlayer insulating film and a coil wire 1602 is formed on theinterlayer insulating film so as to be connected to the coil 1601through the contact hole.

[0176]FIG. 16B is a cross-sectional view taken along the broken lineC-C′ in FIG. 16A.

[0177] In FIG. 16C, a coil wire 1612 is formed on an insulating surfaceand an interlayer insulating film 1613 is formed on the insulatingsurface so as to cover the coil wire 1612. Also, a contact hole isformed in the interlayer insulating film and a coil 1611 is formed onthe interlayer insulating film so as to be connected to the coil wire1612 through the contact hole.

[0178]FIG. 16D is a cross-sectional view taken along the broken lineD-D′ in FIG. 16C.

[0179] It should be noted here that the method of manufacturing a coilused in the present invention is not limited to the method describedabove. A spiral groove is formed by patterning an insulating film and aconductive film is formed on the insulating film so as to cover thegroove. Following this, a structure where the conductive film remainsonly in the groove is obtained by grinding the conductive film throughetching or using a CMP method until the insulating film is exposed. Itis possible to use this conductive film remaining in the groove as acoil.

[0180] It is possible to carry out this embodiment by freely combiningthe structure of this embodiment with the structures of the first tofifth embodiments.

Seventh Embodiment

[0181] In this embodiment, there will be described a structure of aninspection apparatus for performing an inspection using the inspectionmethod of the present invention.

[0182]FIG. 17 is a block diagram of an inspection apparatus of thepresent invention. An inspection apparatus 1700 of the present inventionshown in FIG. 17 includes an inspection substrate 1701, a signal sourceor AC power supply 1702, a means which allows the inspection substrate1701 and a device substrate 1703 to be superimposed on each other sothat a certain space is maintained therebetween (substrate fixing means1704), and a means for identifying each defective spot by measuring anelectric field or electromagnetic wave generated in an inspectiondedicated circuit of the device substrate 1703 (inspection unit 1705).

[0183] It should be noted here that the signal source or AC power supply1702 is regarded as a part of the inspection apparatus in thisembodiment, although there is no problem even if the inspectionapparatus of the present invention does not include the signal source orAC power supply 1702.

[0184] An AC signal generated in the signal source or AC power supply1702 is inputted into an external input buffer 1706 of the inspectionsubstrate 1701. The inputted AC signal is buffer-amplified in theexternal input buffer 1706 and is inputted into a primary coil formingunit 1707 of the inspection substrate 1701.

[0185] In the primary coil forming unit 1707, there is formed primarycoils. Note that in a secondary coil forming unit 1711 of a devicesubstrate 1703, there are formed secondary coils.

[0186] On the other hand, the inspection substrate 1701 and the devicesubstrate 1703 are positioned by a substrate fixing means 1704 so thatthe primary coils of the primary coil forming unit 1707 and thesecondary coils of the secondary coil forming unit 1711 are superimposedon each other, with a certain space being maintained therebetween.

[0187] Then, a power supply voltage or driving signal generated by an ACvoltage that has been generated in the secondary coil forming unit 1711is inputted into a circuit or circuit element 1712 of the devicesubstrate 1703. Note that a circuit that is provided on the devicesubstrate 1703 and generates the power supply voltage or driving signalhas been described in detail in the embodiment mode of the presentinvention. Therefore, the description concerning this circuit is omittedin this embodiment.

[0188] Then, a measuring unit 1708 of the inspection unit 1705 measuresthe strength of the electromagnetic wave or electric field generated inthe circuit or circuit element 1712. Following this, data (measuredvalues) converted into numbers by measurement are sent to an operationunit 1709 of the inspection unit 1705.

[0189] The operation unit 1709 identifies each defective spot on thebasis of the inputted data. In more detail, the operation unit 1709judges each circuit element, in which there is generated an electricfield or electromagnetic wave whose strength greatly differs from thestrength of the electric field or electromagnetic wave generated in anormal circuit element, as a defective spot.

[0190] Several methods of comparing the strengths of electric fields orelectromagnetic waves are listed below.

[0191] (1) A method with which comparison is performed between circuitsor circuit elements provided on the same device substrate that is aninspection target.

[0192] (2) A method with which there is separately prepared a devicesubstrate having a circuit or circuit element that has already beenknown as normal, there is measured the strength of an electromagneticwave or electric field generated in a circuit or circuit element of thisdevice substrate, data obtained by the measurement are stored in amemory or the like, there is measured an electric field orelectromagnetic wave generated in a device substrate that is aninspection target, and the measurement result is compared with the datastored in the memory.

[0193] (3) A method with which the distribution of the strength of anelectric field or electromagnetic wave in accordance with the positionson a device substrate is compared with a mask drawing.

[0194] It should be noted here that the comparison methods describedabove are just a few examples and therefore the present invention is notlimited to them. That is, it is enough that there is detected eachcircuit element in which there is generated an electric field orelectromagnetic wave whose strength greatly differs from the strength ofthe electric field or electromagnetic wave generated in a normal circuitelement.

[0195] It should be noted here that each defective spot is identified bythe inspection unit 1705 in this embodiment, although the inspectionapparatus of the present invention is not limited to this structure.Instead of the inspection unit 1705, there may be used a means forvisualizing the strength of an electromagnetic wave or electric fieldgenerated in the device substrate 1703 to make it possible to directlymake a judgment about the strength of the electromagnetic wave orelectric field using human's eyes.

[0196] It should be noted here that outputs from all circuits or circuitelements that are inspection targets are inputted into the inspectiondedicated circuit. The inspection dedicated circuit includes a means forperforming logical operation processing for a plurality of actuatingsignals inputted from the inspection targets and for outputtingprocessing results as information concerning the operation states of theinspection targets (an operate state, a non-operate state, and a partialoperate state). The inspection dedicated circuit also includes a meansfor amplifying the outputs.

[0197] In this embodiment, the inspection dedicated circuit includes ameans for outputting a signal having a first level only in the casewhere levels of all inputted signals (heights of voltages) areapproximately the same and for outputting a signal having a second levelthat is different from the signal having the first level in the casewhere there exists at least one signal having a different level. Theinspection dedicated circuit also includes a means for amplifying theoutputs.

[0198] Then, the amplified outputs are inputted into a predeterminedterminal (pad) and the strength of an electric field or electromagneticwave generated in the pad is measured. In this manner, there isconfirmed the presence or absence of a defect in each circuit or circuitelement that is an inspection target. Also, it is possible to narroweach area, in which there exists a defective spot, in accordance withthe reduction of the number of circuits or circuit elements connected toone inspection dedicated circuit. It is possible to increase the numberof circuits or circuit elements, for which the presence or absence ofdefects is confirmed by one measurement, in accordance with the increaseof the number of circuits or circuit elements connected to oneinspection dedicated circuit.

[0199] It is possible to carry out this embodiment by freely combiningthe structure of this embodiment with the structures of the first tosixth embodiments.

[0200] With the present invention, there are obtained the structuresdescribed above. This makes it possible to detect each defective spotwithout directly setting up probes on wiring. As a result, it becomespossible to prevent a situation where minute dust caused by the settingup of the probes reduces yield in the following steps. In addition,unlike the optical inspection method, it becomes possible to judgewhether all pattern forming steps have been successfully done or not bya single inspection step. As a result, the inspection step is furthersimplified.

What is claimed is:
 1. An inspection apparatus comprising: at least aprimary coil; a means for superimposing the primary coil and at least asecondary coil of a device substrate on each other so that a certainspace is maintained therebetween; a means for applying an AC voltage tothe primary coil; a means that is connected to the secondary coil andcollects information concerning an electric field generated in aplurality of circuit elements of the device substrate; and a means foridentifying each defective circuit element among the plurality ofcircuit elements of the device substrate on the basis of the collectedinformation.
 2. An inspection apparatus according to claim 1, whereinthe means for collecting the information concerning the electric fieldis a means for measuring a strength of the electric field.
 3. Aninspection apparatus according to claim 2, wherein the means formeasuring the strength of the electric field includes an electroopticdevice.
 4. An inspection apparatus according to claim 3, wherein theelectrooptic device is a Pockels cell.
 5. An inspection apparatuscomprising: at least a primary coil; a means for superimposing theprimary coil and at least a secondary coil of a device substrate on eachother so that a certain space is maintained therebetween; a means forapplying an AC voltage to the primary coil; a means that is connected tothe secondary coil and collects information concerning electromagneticwaves generated in a plurality of circuit elements of the devicesubstrate; and a means for identifying each defective circuit elementamong the plurality of circuit elements of the device substrate on thebasis of the collected information.
 6. An inspection apparatus accordingto claim 5, wherein the means for collecting the information concerningthe electromagnetic waves is a means for measuring a strength of theelectromagnetic waves.
 7. An inspection apparatus according to claim 1,wherein the certain space is controlled by having a gas or a liquid flowbetween the device substrate and an insulating surface on which theprimary coil have been formed.
 8. An inspection apparatus according toclaim 5, wherein the certain space is controlled by having a gas or aliquid flow between the device substrate and an insulating surface onwhich the primary coil have been formed.
 9. An inspection apparatusaccording to claim 1, wherein wires of the primary coil are formed inthe same plane and are also spirally wounded.
 10. An inspectionapparatus according to claim 5, wherein wires of the primary coil areformed in the same plane and are also spirally wounded.
 11. Aninspection apparatus comprising: at least one primary coil; a means forsuperimposing the primary coil and at least one secondary coil of adevice substrate on each other so that a certain space is maintainedtherebetween; a means for applying an AC voltage to the primary coil; ameans that is connected to the secondary coil and collects informationconcerning an electric field generated in a plurality of circuitelements of the device substrate; and a means for identifying eachdefective circuit element among the plurality of circuit elements of thedevice substrate on the basis of the collected information.
 12. Aninspection apparatus comprising: at least one primary coil; a means forsuperimposing the primary coil and at least one secondary coil of adevice substrate on each other so that a certain space is maintainedtherebetween; a means for applying an AC voltage to the primary coil; ameans for collecting information concerning an electric field generatedin an inspection dedicated circuit of the device substrate; and a meansfor identifying each defective circuit element among a plurality ofcircuit elements of the device substrate on the basis of the collectedinformation, wherein outputs from the secondary coil are processed byrectifying waveforms of voltages thereof and are inputted into theplurality of circuit elements of the device substrate, and outputs fromthe plurality of circuit elements are inputted into the inspectiondedicated circuit.
 13. An inspection apparatus according to claim 12,wherein the inspection dedicated circuit includes: a first means foroutputting a signal having a first level if all outputs from theplurality of circuit elements have the same level, and for outputting asignal having a second level that is different from the signal havingthe first level if at least one of the outputs from the plurality ofcircuit elements has a different level; a second means for amplifyingthe output from the first means; and a terminal for inputting an outputfrom the second means.
 14. An inspection apparatus according to claim11, wherein the means for collecting the information concerning theelectric field is a means for measuring a strength of the electricfield.
 15. An inspection apparatus according to claim 12, wherein themeans for collecting the information concerning the electric field is ameans for measuring a strength of the electric field.
 16. An inspectionapparatus according to claim 14, wherein the means for measuring thestrength of the electric field includes an electrooptic device.
 17. Aninspection apparatus according to claim 15, wherein the means formeasuring the strength of the electric field includes an electroopticdevice.
 18. An inspection apparatus according to claim 16, wherein theelectrooptic device is a Pockels cell.
 19. An inspection apparatusaccording to claim 17, wherein the electrooptic device is a Pockelscell.
 20. An inspection apparatus comprising: at least one primary coil;a means for superimposing the primary coil and at least one secondarycoil of a device substrate on each other so that a certain space ismaintained therebetween; a means for applying an AC voltage to theprimary coil; a means that is connected to the secondary coil andcollects information concerning electromagnetic waves generated in aplurality of circuit elements of the device substrate; and a means foridentifying each defective circuit element among the plurality ofcircuit elements of the device substrate on the basis of the collectedinformation.
 21. An inspection apparatus comprising: at least oneprimary coil; a means for superimposing the primary coil and at leastone secondary coil of a device substrate on each other so that a certainspace is maintained therebetween; a means for applying an AC voltage tothe primary coil; a means for collecting information concerningelectromagnetic waves generated in an inspection dedicated circuit ofthe device substrate; and a means for identifying each defective circuitelement among a plurality of circuit elements of the device substrate onthe basis of the collected information, wherein outputs from thesecondary coil are processed by rectifying waveforms of voltages thereofand are inputted into the plurality of circuit elements of the devicesubstrate, and outputs from the plurality of circuit elements areinputted into the inspection dedicated circuit.
 22. An inspectionapparatus according to claim 21, wherein the inspection dedicatedcircuit includes: a first means for outputting a signal having a firstlevel if all outputs from the plurality of circuit elements have thesame level, and for outputting a signal having a second level that isdifferent from the signal having the first level if at least one of theoutputs from the plurality of circuit elements has a different level; asecond means for amplifying the output from the first means; and aterminal for inputting an output from the second means.
 23. Aninspection apparatus according to claim 20, wherein the means forcollecting the information concerning electromagnetic waves is a meansfor measuring a strength of electromagnetic waves.
 24. An inspectionapparatus according to claim 21, wherein the means for collecting theinformation concerning electromagnetic waves is a means for measuring astrength of electromagnetic waves.
 25. An inspection apparatus accordingto claim 11, wherein the certain space is controlled by having a gas ora liquid flow between the device substrate and an insulating surface onwhich the plurality of primary coil have been formed.
 26. An inspectionapparatus according to claim 12, wherein the certain space is controlledby having a gas or a liquid flow between the device substrate and aninsulating surface on which the plurality of primary coil have beenformed.
 27. An inspection apparatus according to claim 20, wherein thecertain space is controlled by having a gas or a liquid flow between thedevice substrate and an insulating surface on which the plurality ofprimary coil have been formed.
 28. An inspection apparatus according toclaim 21, wherein the certain space is controlled by having a gas or aliquid flow between the device substrate and an insulating surface onwhich the plurality of primary coil have been formed.
 29. An inspectionapparatus according to claim 11, wherein wires of the plurality ofprimary coil are formed in the same plane and are also spirally wounded.30. An inspection apparatus according to claim 12, wherein wires of theplurality of primary coil are formed in the same plane and are alsospirally wounded.
 31. An inspection apparatus according to claim 20,wherein wires of the plurality of primary coil are formed in the sameplane and are also spirally wounded.
 32. An inspection apparatusaccording to claim 21, wherein wires of the plurality of primary coilare formed in the same plane and are also spirally wounded.
 33. Aninspection method comprising the following steps of: superimposing atleast one primary coil, which has been formed on a first insulatingsurface and to which an AC voltage is applied, and a secondary coilformed on a second insulating surface on each other, with a certainspace being maintained therebetween; collecting information concerningelectric fields or electromagnetic waves generated in a plurality ofcircuit elements that have been formed on the second insulating surfaceand are connected to the secondary coil; and identifying each defectivecircuit element among the plurality of circuit elements of the devicesubstrate on the basis of the collected information.
 34. An inspectionmethod according to claim 33, wherein wires of the primary coil areformed in the same plane and are also spirally wounded.
 35. Aninspection method comprising the following steps of: superimposing aplurality of primary coils formed on a first insulating surface and aplurality of secondary coils formed on a second insulating surface oneach other, with a certain space being maintained therebetween; applyingAC voltages, whose phases are different from each other, to theplurality of primary coils; generating a DC voltage by rectifyingvoltages generated in the plurality of secondary coils and combining therectified voltages; applying the DC voltage to a plurality of circuitelements formed on the second insulating surface; collecting informationconcerning electric fields or electromagnetic waves generated in theplurality of circuit elements; and identifying each defective circuitelement among the plurality of circuit elements of the device substrateon the basis of the collected information.
 36. An inspection methodcomprising the following steps of: superimposing a plurality of primarycoils formed on a first insulating surface and a plurality of secondarycoils formed on a second insulating surface on each other, with acertain space being maintained therebetween; applying an AC voltage tothe plurality of primary coils; generating a driving signal fromvoltages generated in the plurality of secondary coils; applying thedriving signal to a plurality of circuit elements formed on the secondinsulating surface; collecting information concerning electric fields orelectromagnetic waves generated in the plurality of circuit elements;and identifying each defective circuit element among the plurality ofcircuit elements of the device substrate on the basis of the collectedinformation.
 37. An inspection method comprising the following steps of:superimposing a plurality of primary coils formed on a first insulatingsurface and a plurality of secondary coils formed on a second insulatingsurface on each other, with a certain space being maintainedtherebetween; applying an AC voltage to the plurality of primary coils;generating a driving signal in a waveform shaping circuit formed on thesecond insulating surface using voltages generated in the plurality ofsecondary coils; applying the driving signal to a plurality of circuitelements formed on the second insulating surface; collecting informationconcerning electric fields or electromagnetic waves generated in theplurality of circuit elements; and identifying each defective circuitelement among the plurality of circuit elements of the device substrateon the basis of the collected information.
 38. An inspection methodcomprising the following steps of: superimposing a plurality of firstprimary coils formed on a first insulating surface and a plurality offirst secondary coils formed on a second insulating surface on eachother so that a certain space is maintained therebetween, andsuperimposing a plurality of second primary coils formed on the firstinsulating surface and a plurality of second secondary coils formed onthe second insulating surface on each other so that a certain space ismaintained therebetween; applying AC voltages, whose phases aredifferent from each other, to the plurality of first primary coils;generating a DC voltage by rectifying voltages generated in theplurality of first secondary coils and combining the rectified voltages;applying an AC voltage to the plurality of second primary coils;generating a driving signal from voltages generated in the plurality ofsecond secondary coils; applying the DC voltage and the driving signalto a plurality of circuit elements formed on the second insulatingsurface; collecting information concerning electric fields orelectromagnetic waves generated in the plurality of circuit elements;and identifying each defective circuit element among the plurality ofcircuit elements of the device substrate on the basis of the collectedinformation.
 39. An inspection method according to claim 38, wherein thedriving signal is generated in a waveform shaping circuit.
 40. Aninspection method according to claim 35, wherein wires of the pluralityof primary coils are formed in the same plane and are also spirallywounded.
 41. An inspection method according to claim 36, wherein wiresof the plurality of primary coils are formed in the same plane and arealso spirally wounded.
 42. An inspection method according to claim 37,wherein wires of the plurality of primary coils are formed in the sameplane and are also spirally wounded.
 43. An inspection method accordingto claim 38, wherein wires of the plurality of primary coils are formedin the same plane and are also spirally wounded.
 44. An inspectionmethod according to claim 33, wherein the means for collecting theinformation concerning the electric field is a means for measuring astrength of the electric field.
 45. An inspection method according toclaim 35, wherein the means for collecting the information concerningthe electric field is a means for measuring a strength of the electricfield.
 46. An inspection method according to claim 36, wherein the meansfor collecting the information concerning the electric field is a meansfor measuring a strength of the electric field.
 47. An inspection methodaccording to claim 37, wherein the means for collecting the informationconcerning the electric field is a means for measuring a strength of theelectric field.
 48. An inspection method according to claim 38, whereinthe means for collecting the information concerning the electric fieldis a means for measuring a strength of the electric field.
 49. Aninspection method according to claim 44, wherein the means for measuringthe strength of the electric field includes an electrooptic device. 50.An inspection method according to claim 45, wherein the means formeasuring the strength of the electric field includes an electroopticdevice.
 51. An inspection method according to claim 46, wherein themeans for measuring the strength of the electric field includes anelectrooptic device.
 52. An inspection method according to claim 47,wherein the means for measuring the strength of the electric fieldincludes an electrooptic device.
 53. An inspection method according toclaim 48, wherein the means for measuring the strength of the electricfield includes an electrooptic device.
 54. An inspection methodaccording to claim 49, wherein the electrooptic device is a Pockelscell.
 55. An inspection method according to claim 50, wherein theelectrooptic device is a Pockels cell.
 56. An inspection methodaccording to claim 51, wherein the electrooptic device is a Pockelscell.
 57. An inspection method according to claim 52, wherein theelectrooptic device is a Pockels cell.
 58. An inspection methodaccording to claim 53, wherein the electrooptic device is a Pockelscell.
 59. An inspection method comprising the following steps of:superimposing a plurality of primary coils formed on a first insulatingsurface and a plurality of secondary coils formed on a second insulatingsurface on each other so that a certain space is maintainedtherebetween; applying AC voltages, whose phases are different from eachother, to the plurality of primary coils; generating a DC voltage byrectifying voltages generated in the plurality of secondary coils andcombining the rectified voltages; applying the DC voltage to a pluralityof circuit elements formed on the second insulating surface; inputtingoutputs from the plurality of circuit elements into an inspectiondedicated circuit; collecting information concerning an electric fieldor electromagnetic waves generated in a terminal of the inspectiondedicated circuit; and identifying each defective circuit element amongthe plurality of circuit elements of the device substrate on the basisof the collected information.
 60. An inspection method comprising thefollowing steps of: superimposing a plurality of primary coils formed ona first insulating surface and a plurality of secondary coils formed ona second insulating surface on each other so that a certain space ismaintained therebetween; applying an AC voltage to the plurality ofprimary coils; generating a driving signal in a waveform shaping circuitformed on the second insulating surface using voltages generated in theplurality of secondary coils; applying the driving signal to a pluralityof circuit elements formed on the second insulating surface; inputtingoutputs from the plurality of circuit elements into an inspectiondedicated circuit; collecting information concerning an electric fieldor electromagnetic waves generated in a terminal of the inspectiondedicated circuit; and identifying each defective circuit element amongthe plurality of circuit elements provided on the device substrate onthe basis of the collected information.
 61. An inspection methodaccording to claim 59, wherein the inspection dedicated circuitincludes: a first means for outputting a signal having a first level ifall outputs from the plurality of circuit elements have the same level,and for outputting a signal having a second level that is different fromthe signal having the first level if at least one of the outputs fromthe plurality of circuit elements has a different level; and a secondmeans for amplifying the output from the first means, wherein an outputfrom the second means is inputted into the terminal.
 62. An inspectionmethod according to claim 60, wherein the inspection dedicated circuitincludes: a first means for outputting a signal having a first level ifall outputs from the plurality of circuit elements have the same level,and for outputting a signal having a second level that is different fromthe signal having the first level if at least one of the outputs fromthe plurality of circuit elements has a different level; and a secondmeans for amplifying the output from the first means, wherein an outputfrom the second means is inputted into the terminal.
 63. An inspectionmethod according to claim 59, wherein the means for collecting theinformation concerning the electric field is a means for measuring astrength of the electric field.
 64. An inspection method according toclaim 60, wherein the means for collecting the information concerningthe electric field is a means for measuring a strength of the electricfield.
 65. An inspection method according to claim 63, wherein the meansfor measuring the strength of the electric field includes anelectrooptic device.
 66. An inspection method according to claim 64,wherein the means for measuring the strength of the electric fieldincludes an electrooptic device.
 67. An inspection method according toclaim 65, wherein the electrooptic device is a Pockels cell.
 68. Aninspection method according to claim 66, wherein the electrooptic deviceis a Pockels cell.
 69. An inspection method according to claim 59,wherein wires of the primary coils are formed in the same plane and arealso spirally wounded.
 70. An inspection method according to claim 60,wherein wires of the primary coils are formed in the same plane and arealso spirally wounded.
 71. An inspection method according to claim 33,wherein the certain space is controlled by having a gas or a liquid flowbetween the first insulating surface and the second insulating surface.72. An inspection method according to claim 35, wherein the certainspace is controlled by having a gas or a liquid flow between the firstinsulating surface and the second insulating surface.
 73. An inspectionmethod according to claim 36, wherein the certain space is controlled byhaving a gas or a liquid flow between the first insulating surface andthe second insulating surface.
 74. An inspection method according toclaim 37, wherein the certain space is controlled by having a gas or aliquid flow between the first insulating surface and the secondinsulating surface.
 75. An inspection method according to claim 38,wherein the certain space is controlled by having a gas or a liquid flowbetween the first insulating surface and the second insulating surface.76. An inspection method according to claim 59, wherein the certainspace is controlled by having a gas or a liquid flow between the firstinsulating surface and the second insulating surface.
 77. An inspectionmethod according to claim 60, wherein the certain space is controlled byhaving a gas or a liquid flow between the first insulating surface andthe second insulating surface.